The invention relates to an apparatus or method for transporting sheets or plies superimposed and directly interconnected via a transition, termed fold in the following. The sheet layers, such as paper, are then in direct contact by their insides and form an outside by outer mutually remote faces. The insides transit via the concave curved inside of the fold and the outer faces transit via the convex curved outside of the fold. The sheets may be multi-layer on each of the two fold sides and within the fold. Then the insides are formed by the innermost layer and the outsides by the outer-most layer between which further layers are located. Such sheet piles to be folded or already folded are further processed into e.g. exercise books.
Reference is made to a transport and folding apparatus known from German patent 25 19 420 as included in the present invention with which even deep piles of sheets may be folded by a simple configuration at high speed without the risk of inherent crushing.
When the folded sheet is withdrawn from the inserter or folding blade relatively high friction may occur. The blade ensures, however, a smooth transfer of the sheet directly to a conveyor, e.g. so that it is not pulled apart. Thereby, however, the conveyor""s pressure against the outside of the sheet acts via the inside directly on the blade. Thus withdrawing the blade is empeded and limits the working speed.
An object is to provide an apparatus or a method which avoids the disadvantages of known configurations or of the kind as described. Furthermore, it is intended to enable the friction with which the sheet is withdrawn from the inserter to be reduced or the working speed to be increased.
According to the invention means are provided by which the sheet is passed on to the conveyor so that the transverse or cross force of the latter acting on the outside is transmitted to the inserter only non-significantly or to a negligible degree. This cross force commonly acts on all sheets by clamping so that the sheets will not be mutually displaced due to the conveying force oriented transverse to the cross force. The sheets are transported solely by the positive friction contact with the outside. Transfer of the friction pressure to the contact between sheet and inserter is significantly reduced or even eliminated.
The impact for forcing the sheet into conveying engagement may take place in the region of an opening or discontinuity of the inserter and upstream of the conveyor on the outside. Preferably this opening at the end of the inserter is an open cutout. At this cutout the conveyor engages the outside of the sheet. Thus the conveyor presses the sheets within the opening directly against each other by their insides and not against the inserter.
Prior to reaching the conveyor these openings of the inserter may be closed with fillers. Thus the inserter""s end is initially also in contact with the fold""s inside at the corresponding opening zone to be opened thereafter. Thus the fold""s inside or crease is formed continuously and evenly by the inserter. Prior to or while reaching the conveyor the opening""s filler is removed or retracted. Thus the filler remains outside the narrowest zone of the infeed mouth of the conveying gap but may, however, protrude as far as into the flare of this gap.
The invention is expedient wherever sheets need to be withdrawn from an inserter or engaging member with reduced friction. It may also be advantageous to configure a member which engages the outside of the sheet with pressure and comotion like the conveyor so that its frontmost portion as viewed in the feed direction exerts the highest pressure. Portions of the pressing face directly adjoining downstream thereof exert a lower pressure, e.g. whilst the pressing face rolls along the outer face of the sheet. Thus the fold is additionally creased or pressed flat by being rolled against the inserter without adjoining portions of the outside exposed to an unnecessarily high pressure.
The transport or driving face which engages the outside of the sheet can be movable transverse to the outside of the sheet independent of its conveying motion. If the conveyor is a nipper or gripper its gap is widenable and closeable. Thus the pressure against the sheet""s outside is variable or totally eliminatable. The fold can be introduced in the running direction between the jaws of the conveying nipper while simultaneously laying the jaws against the sheet""s outsides and increasing the clamping force. Simultaneously the driving face of the nipper runs commonly with the sheet or inserter at the same speed and running direction. Thus a very gentle transfer is achieved. Thereby the nipper too, may press the fold flat or maintain it flat-pressed.
Although for controlling the motion sequences of the inserter, the transverse displacement of the conveyor, of the pressing faces electronic, hydraulic or pneumatic control means are feasible, mechanical control means are preferred. These may include a cam control. The followers guided by the curve or cam bodies are positively connected via transfer drives to the member to be controlled in each case. The transfer drive may comprise a leverage or push and pull rods or be formed solely by these.
By the method of the invention the sheet is transferred by the inserter and/or the pressing member to the conveyor, but the inserter is not exposed to the contact pressure of the conveyor.